Heikki Valentin Klemetti (14.2. 1876 Kuortane – 26.8. 1953 Helsinki) was a Finnish composer, arranger, music critic and choir conductor. He has been one of the most significant pioneers and developers of Finnish choral music.

Klemetti graduated with a Master of Philosophy in 1899 and also studied at the Helsinki Orchestra School, the Berlin Music Academy and the Stern Conservatory. He was awarded the title of professor in 1923. The University of Helsinki awarded Klemetti an honorary doctorate in philosophy in 1936 and an honorary doctorate in theology in 1946.

Klemetti conducted numerous choirs and founded the Suomen Laulu choir in 1900, which he conducted until 1942. It began as a male choir, but later expanded to a mixed choir. Klemetti made his debut on December 1898 at a concert of the YL Male Voice Choir and led the YL for a total of 30 years.

Klemetti was also known as a sharp-tongued music critic. Music history was another subject of his writing. His entire activity was guided by a strong nationalist sentiment.